Fulcio is a certificate authority for issuing code signing certificates for an OpenID Connect (OIDC) identity. Versions through 1.8.5 improperly follow cross-host redirects and attach Kubernetes ServiceAccount tokens during OIDC discovery, allowing a malicious or compromised issuer to perform blind SSRF, substitute and cache malicious JWKS keys, or disclose ServiceAccount tokens to external hosts. Version 1.8.6 blocks cross-host redirects, restricts token injection, and restricts local token loading. No known workarounds are available.
Weakness
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Red Hat Advanced Cluster Security for Kubernetes 4.10 | RedHat | advanced-cluster-security/rhacs-main-rhel8:1785420959 | * |
| Red Hat Advanced Cluster Security for Kubernetes 4.9 | RedHat | advanced-cluster-security/rhacs-main-rhel8:1785413210 | * |
| Golang-github-sigstore-fulcio | Ubuntu | upstream | * |